Papers by Daniel Villatoro
Zusammenfassung: This volume contains the papers presented at the Student Session of the 11th Eur... more Zusammenfassung: This volume contains the papers presented at the Student Session of the 11th European Agent Systems Summer School (EASSS) held on 2nd of September 2009 at Educatorio della Providenza, Turin, Italy. The Student Session, organised by students, is designed to encourage student interaction and feedback from the tutors.
One of the main tasks to be performed in the eRep project is a set of experiments to evaluate dif... more One of the main tasks to be performed in the eRep project is a set of experiments to evaluate different reputation systems in different environments. These experiments are an essential input for the white book and include experiments with autonomous agents, experiments with humans and hybrid experiments where humans and autonomous agents are put together in the same environment.
Abstract Recent studies show that punishment plays a crucial role in favoring and maintaining soc... more Abstract Recent studies show that punishment plays a crucial role in favoring and maintaining social order. However, very little attention has been paid so far to the potential of distributed punishment. In this work we put forward the hypothesis that distributed punishment is more effective than individual punishment, because is more persuasive in conveying messages of peer condemnation and of shared norm defense.
Abstract���The use of social norms has proven to be effective in the self-governance of decentral... more Abstract���The use of social norms has proven to be effective in the self-governance of decentralised systems in which there is no central authority. Axelrod's seminal model of norm establishment in populations of self-interested individuals provides some insight into the mechanisms needed to support this through the use of metanorms, but is not directly applicable to real world scenarios such as online peer-to-peer communities, for example. In particular, it does not reflect different topological arrangements of interactions.
Abstract. In human societies, exchanging social information is fundamental for partner selection,... more Abstract. In human societies, exchanging social information is fundamental for partner selection, cooperation, social control and coalition formation, but it also plays a role in social comparison and group cohesion, just to name some of its main functions. Reputation spreading is a social activity that plays a fundamental role in social control and partner selection, and spreading reputation about noncooperators has proven to be effective in increasing levels of cooperation both in natural and artificial experimental settings.
… , Institutions and Norms in Agent Systems IV, Jan 1, 2009
Our main interest research is focused on reaching a decentralized form of social order through th... more Our main interest research is focused on reaching a decentralized form of social order through the usage of social norms in virtual communities. In this paper, we analyze the effects of different sets of social norms within a society. The simulation scenario used for the experiments is a metaphor of a resource-gatherer prehistoric society. Finally, we obtain a qualitative ranking of all the possible sets of social norms in our scenario performing agent-based simulation.
Proceedings of 3rd international …, Jan 1, 2009
Social conventions are useful self-sustaining protocols for groups to coordinate behavior without... more Social conventions are useful self-sustaining protocols for groups to coordinate behavior without a centralized entity enforcing coordination. The emergence of such conventions in different multi agent network topologies has been investigated by several researches. Although we will perform an exhaustive study of different network structures, we are concerned that different topologies will affect the emergence in different ways. Therefore, the main research question in this work is comparing and studing effects of different topologies on the emergence of social conventions. While others have investigated memory for learning algorithms, the effects of memory on the reward have not been investigated thoroughly. We propose a reward metric that is derived directly from the history of the interacting agents. The reward metric is the majority rule, thus the emerging convention becomes self propagating in the society. Agents are proportionally rewarded based upon their conformity to the majority action when interacting with another agent. Another research question to be answered is what effect does the history based reward function have on convergence time in different topologies. We also investigate the effects of history size, agent population size and neighborhood size proving their effects by agent-based experimentation.
2009 IEEE/WIC/ACM International …, Jan 1, 2009
Social conventions are useful self-sustaining protocols for groups to coordinate behavior without... more Social conventions are useful self-sustaining protocols for groups to coordinate behavior without a centralized entity enforcing coordination. We perform an in-depth study of different network structures, to compare and evaluate the effects of different network topologies on the success and rate of emergence of social conventions. While others have investigated memory for learning algorithms, the effects of memory or history of past activities on the reward received by interacting agents have not been adequately investigated. We propose a reward metric that takes into consideration the past action choices of the interacting agents. The research question to be answered is what effect does the history based reward function and the learning approach have on convergence time to conventions in different topologies. We experimentally investigate the effects of history size, agent population size and neighborhood size or the emergence of social conventions.
AI Communications, Jan 1, 2010
Internalization is at study in social-behavioural sciences and moral philosophy since long; of la... more Internalization is at study in social-behavioural sciences and moral philosophy since long; of late, the debate was revamped within the rationality approach to the study of cooperation and compliance since internalization is a less costly and more reliable enforcement system than social control. But how does it work? So far, poor attention was paid to the mental underpinnings of internalization. This paper advocates a rich cognitive model of different types, degrees and factors of internalization. In order to check the individual and social effect of internalization, we have adapted an existing agent architecture, EMIL-A, providing it with internalization capabilities, turning it into EMIL-I-A. Experiments have proven satisfactory results with respect to the maintenance of cooperation in a proof-of-concept simulation.
Proc. of CAEPIA'07, Jan 1, 2007
In this paper we present a technological framework that allows virtual cognitive agents and human... more In this paper we present a technological framework that allows virtual cognitive agents and humans using a web interface to participate in the same electronic institution (eI). Given that the main objective of this framework is to perform experiments on the use of reputation, we also introduce the notion of reputation within the eI to incorporate the circulation of opinions about other agents towards certain actions, and we extend the actual eI infrastructure to permit BDI agents to participate in an eI.
Proceedings of the 6th European workshop …, Jan 1, 2008
This paper examines the decentralized formation of groups within a multiagent normative society. ... more This paper examines the decentralized formation of groups within a multiagent normative society. In our case, a group is defined based on the set of social norms used by its members: all the agents using the same set of norms belong to the same social group. In this paper we explore different mechanisms that allow agents to recognize the others as members of a certain social group. Considering as the basic mechanism the one that makes agents interact with other agents without considering the previous interactions and with no communication, three new algorithms have been developed and tested to improve the efficiency of the basic one. These algorithms are: (1) the whitelisting algorithm, which works as a recomender of trusted neighbours; (2) the blacklisting algorithm, whose basic functioning is based on defaming the non-related agents inside a certain social group; and (3) the labelling algorithm, which basically publishes information of the interactions with different agents allowing the rest to access that information. Simulation results are shown, confirming that these algorithms improve the efficiency of the basic one. Finally, we present and discuss some of the weak points of the algorithms presented as well as future improvements.
Proceedings of the 5th conference of the …, Jan 1, 2008
Social Norms proliferate in societies as a mechanism for self-organization. This kind of norms ar... more Social Norms proliferate in societies as a mechanism for self-organization. This kind of norms are not enforced by a central authority and the individuals of the society are those responsible for their generation and maintenance. The maintenance process is what is known as norm support and is supported by several mechanisms like for example laws, social proof, dominance, etc. We believe that agent based simulation is a suitable technique for investigating this topic. In this paper we present a simulated society of virtual agents which helps us studying the effects of a social evaluation like the Image as a mechanism to ensure the norm support process in a society with liars. Intimately related, we also introduce the concept of Visionary agent (individual that can evaluate norms before trying them in the real society) and study its effect on simulations.
International Journal of Agent …, Jan 1, 2010
… , 2009. CEC'09. IEEE Congress on, Jan 1, 2009
This paper examines the decentralized recognition of groups within a multiagent normative society... more This paper examines the decentralized recognition of groups within a multiagent normative society in dynamic environments. In our case, a social group is defined based on the set of social norms used by its members. These social norms regulate interactions under certain situations, and situations are determined by the environmental conditions. Environmental conditions might change unexpectedly, and so should the notion of social group for each agent. Consequently, agents need mechanisms to adjust their notion of group dynamically and accordingly the agents with whom it is socially related. In this work we analyze how different algorithms (whitelisting, blacklisting, labelling), that allow agents to recognize the others as members of a certain social group, behave in these dynamic environments. Simulation results are shown, confirming that the limited memory approach reacts better against environmental changes. Moreover we compare two approaches that regulate the adaptation of the relevance of norms and the notion of group: the unlimited normative memory and the limited memory.
Proceedings of 21st European Simulation and …, Jan 1, 2007
In this work we present a mechanism designed for the selection of a suitable set of social norms ... more In this work we present a mechanism designed for the selection of a suitable set of social norms that would regulate a simulated virtual society. The approach taken for this selection problem is a combination of Genetic algorithms and Simulation. A resource-gathering society has been built using Repast, and on top of it, the genetic algorithm that finds the social norms.
Proceedings of 8th …, Jan 1, 2010
As specified by Axelrod in his seminal work "An Evolutionary Approach to Norms", punishment is a ... more As specified by Axelrod in his seminal work "An Evolutionary Approach to Norms", punishment is a key mechanism in a self-regulated society to achieve the necessary social control and to impose certain norms. In this paper, we distinguish between punishment and sanction, focusing on the specific ways in which these two different mechanisms favor the emergence of cooperation and the spreading of social norms within a social system. To achieve this task, we have developed a normative agent able to recognize and impose on defectors either punishment and sanction, and have implemented an proof-of-concept simulation model to test our hypotheses.
… of The 8th International Conference on …, Jan 1, 2009
This paper examines the decentralized recognition of groups within a multiagent normative society... more This paper examines the decentralized recognition of groups within a multiagent normative society. In this work we explore different mechanisms that allow agents to recognize the others as members of a certain social group. Considering as the basic mechanism the one that makes agents interact with other agents without considering the previous interactions and with no communication, three new algorithms have been developed and tested to improve the efficiency of the basic one. These algorithms are: (1) the whitelisting, (2) the blacklisting, and (3) the labelling algorithm. Moreover, a reinterpretation of the definition of group is done in order to make it more dynamic and flexible with respect to the environment where agents are located. Analysis on simulation results confirms the effectiveness of this dynamic member evaluation function.
Proceedings of The 8th …, Jan 1, 2009
In this paper we present an application build on top of electronic institutions in order to creat... more In this paper we present an application build on top of electronic institutions in order to create a remote experimental platform for human and virtual agents. Our software objectives are twofold: (1) provide experiment designers with a tool to design an experiment where human and virtual agents will interact, and, (2) provide experimental subjects with a friendly interface to interact with virtual agents through an electronic institution.
Deontic Logic in Computer Science, Jan 1, 2010
ijcai.org
As explained by Axelrod in his seminal work An Evolutionary Approach to Norms, punishment is a ke... more As explained by Axelrod in his seminal work An Evolutionary Approach to Norms, punishment is a key mechanism to achieve the necessary social control and to impose social norms in a self-regulated society. In this paper, we distinguish between two enforcing mechanisms. i.e. punishment and sanction, focusing on the specific ways in which they favor the emergence and maintenance of cooperation.
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Papers by Daniel Villatoro